Temperature-regulation for flat offset presses

ABSTRACT

IN A STRUCTURE FOR REGULATING THE TEMPERATURE OF BEDS OF FLAT OFFSET PRESSES, SUPPORTING PRINTING PLATES, THE BED HAS AN UPWARDLY DIRECTED SURFACE TO BE ENGAGED BY THE PRINTING PLATE AND AT ITS SIDE DIRECTED AWAY FROM SAID UPPER SURFACE A PLURALITY OF STRENGTHENING RIBS WHICH INTERSECT EACH OTHER TO FORM CELLS HAVING OPEN BOTTOM ENDS. A TEMPERATURE-REGULATING ASSEMBLY COACTS WITH SAID CELLS FOR REGULATING THE TEMPERATURE OF THE BED TO MAINTAIN THE LATTER AT A UNIFORM CONSTANT PREDETERMINED TEMPERATURE. AN ENCLOSURE IS CONNECTED WITH SAID BED FOR ENCLOSING THE TEMPERATURE-REGULATING STRUCTURE.

United States Patent l l l 1 1 1 1 Inventor Willy Hirsch Buchackersiedlung, Gronau, Wurttemberg, Germany Appl.No. 831,667 Filed June 9, 1969 Patented June 28, 1971 Priority June 14, 1968 Germany 1 17 61 605.6

TEMPERATURE-REGULATION FOR FLAT OFFSET PRESSES 8 Claims, 3 Drawing Figs.

U.S. Cl ..1 10l/287, 51/266, 101/382, 165/75, 165/122, 165/163 Int. Cl 84113/52 Field of Search 101/287,

382, 316; 165/75 (Cursory), 121 (Cursory), 122 (Cursory), 157 (Cursory), 163 (Cursory); 51/165,30, 266; 83/(lnquired); 269/(lnquired); 239/(lnquired); 62/(lnquired) [56] References Cited UNITED STATES PATENTS 620,139 1899 Hysore 165/121X 1,475,963 12/1923 Osterlind 101/382 1,747,962 2/1930 Wichmann 101/382 1,843,471 2/1932 Wood........... 51/266X 2,209,505 7/1940 Bole et a1... 51/266X 2,071,033 2/1937 Hanna 51/266X 2,156,699 5/1939 Owen 5 l/266X Primary ExaminerRobert E. Pulfrey Assistant ExaminerC. Coughenour Attorney-Richard Low ABSTRACT: In a structure for regulating the temperature of beds of flat offset presses, supporting printing plates, the bed has an upwardly directed surface to be engaged by the printing plate and at its side directed away from said upper surface a plurality of strengthening ribs which intersect each other to form cells having open bottom ends. A temperature-regulating assembly coacts with said cells for regulating the temperature of the bed to maintain the latter at a uniform constant predetermined temperature. An enclosure is connected with said bed for enclosing the temperature-regulating structure.

} PATENTED JUN28 l97| SHEET 2 BF 2 INVENTOR. O 0 /7?) (6 QKaM/Z TEMPERATURE-REGULATION FOR FLAT OFFSET PRESSES BACKGROUND OF THE INVENTION The present invention relates to flat offset presses.

More particularly, it relates to a structure for controlling the temperature of beds of flat offset presses, which support printing plates. 7

With flat offset presses it is necessary to provide temperature regulation ofthe surface which supports the printing plate so that during the printing operations there will be substantially no evaporation of moisture supplied by way of moisturesupplying rolls. It is possible to prevent evaporation by maintaining the bed which carries the printing plate constantly in the region of the condensation point of the moisture. In this way it is also possible to maintain the amount of moistureforming water, which is required, at a minimum as contrasted with operation without temperature regulation. 1

This ensures the advantage of substantially eliminating any emulsifying of the ink delivered to the printing plate so that a more sharply printed product can be obtained. With temperature regulation of the bed which carries the printing plate it becomes possible to use printing plates of smoother exterior surfaces. Also, when printing in several colors on paper or other hygroscopic materials the smaller amount of water that is required results in a superior matching. Moreover, at a temperature of 8 to l below the condensation point it is possible to do away with the delivery of moisture to the printing plate inasmuch as condensation water will form at such a temperature.

With known presses the temperature regulation of the bed of the printing plateis carried out in such a way that directly beneath the upper surface of the bed there are parallel passages through which a temperature-controlling liquid such as water flows. However, experience has shown that with such an arrangement no uniform and constant temperature throughout the entire bed can be achieved. Nor can a uniform and constant temperature for the bed be achieved when a temperature-regulating plate formed with passages therethrough is placed on the bed.

SUMMARY OF THE INVENTION It is accordingly a primary object of the invention to provide a temperature-regulating structure which will avoid the above referred to drawbacks.

In particular, it is an object of the invention to provide an assembly for a flat offset press, which will maintain the bed that carries the printing plate at a uniform and constant preselected temperature, especially at the upper surface of the bed which directly supports the printing plate.

Another object of the invention is to achieve these results with a bed which is ofan extremely strong construction.

A further object of the invention is to provide a construction which is composed of simple rugged elements that operate very reliably to achieve the desired results with a minimum of cost both from the standpoint of the structure itself as well as from the standpoint of its operation,

In order to achieve the envisaged results the bed which carries the printing plate is provided at its underside with a plurality of cells that have open bottom ends. A temperatureregulating medium communicates with the cells through the open bottom ends thereof, and may be in the form of air which is directed into the cells and maintained at a preselected temperature, or in the form of a liquid which is sprayed into the cells and again maintained at preselected temperature. An ,en closure is removably connected with the bed in a fluidtig'ht manner and serves to enclose the temperature-regulating means. The advantage of this enclosure resides in the fact that it prevents a constantly recirculating temperature-regulating fluid from escaping beyond the circulating system. For the construction of this enclosure it is possible to use a vat which may have, for example, a double wall where the gap between the walls accommodates an intermediate layer of a material of poor heat conductivity.

The primary advantages achieved by the invention reside in the fact that strengthening ribs which extend downwardly through a substantial distance in order to form the cells provide a very substantially enlargement of the exterior surface of the bed so that the mass of the latter is brought directly into contact with the temperature-controlling medium. Thus, a better heat or cold transfer and storage in'the bed supporting the printing plate and a more uniform distribution of the temperature-controlling medium are achieved. The result is that the upwardly directed operating surface of the bed, which directly carries the printing plate, is provided over its entire area with a uniform constant temperature.

BRIEF DESCRIPTION OF THE DRAWINGS of a temperature-regulating means, namely, one which uses a liquid as the temperature-regulating medium; and

FIG. 3 is a view of the structure of FIG. 2, as seen from below with the vat removed, except for the outlet drain thereof, so as to show the details of the liquid-supply network as well as the location of the discharge from the lowermost part of the vat.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to FIG. 1, the offset press illustrated is composed primarily of a frame 11 which is formed by a pair of parallel lateral stands between which the printing plate bed 14 with the printing plate 13 thereon is arranged. The lateral stands carry rails which serve for the back-and-forth movement of a cylinder carriage 15 that rides on rollers. The carriage 15 supports a printing cylinder 16 for rotary movement.

In the operating direction there is situated in advance of the printing cylinder 16 an inking mechanism 17 which is made up, for instance, of ink-transfer rollers 18 and several ink-applying rollers 19 which are also rotatably supported by the cylinder carriage 15.

Behind the printing cylinder is a moisturizing mechanism 34 made up of a transfer roll 20, a pair of wiper rolls 21, and a pair of supply rolls 22. The rollers of the dampening or moisturizing mechanism 34 are also supported by the cylinder carriage 15. The inking mechanism 17 receives its ink from an ink supply while the moisturizing mechanism 34 receives water from a suitable water tank. The ink supply and water tank as well as the counter printing plate which serves to receive the printed material are for the sake of clarity as well as for the reason that these components do form no part of the present invention are not shown.

The inking mechanism and moisturizing mechanism serve to ink and moisturize the printing plate 13 carried by the bed 14. The locations of the printing plate 13 which have been inked are transferred by means of the printing cylinder to the material already situated in readiness on the counter printing support, such as paper, glass, wood, or other suitable material.

In the embodiments selected for illustration, the printing plate beds, as they are customarily used with flat offset presses of the present type, are provided in accordance with the inventionwith different types of temperature-regulating mechanisms.

In the embodiment of FIG. 1, the bed 14 has its temperature controlled by air. For this purpose the bed 14 has strengthening ribs 23 which projectfrom, and intersect each other at, the side of the bed opposed from its upper surface that carries the printing plate. These ribs are arranged so as to form boxshaped cells 24 which are open at their bottom ends and which terminate at their top ends in surface portions of the bed directed away from the upper surface thereof.

Directly beneath the cells 24, adjacent the open bottom ends thereof, it is the temperature-regulating means which takes the form of containerlike elements 25 shaped, for instance, as conduits, tubes, circulating loops, coils, or the like, through which a suitable temperature-regulating fluid, either gas or liquid, flows. The temperature-regulating means also includes fans 26 which distribute the air by directing same past the elements 25 so that the temperature of the air is controlled thereby. Thus, the elements or containers 25, with gas or liquid flowing therethrough, will provide for the air a temperature which will control the temperature for the bed 14. lnstead of fluid-conveying loops or coils, it is possible for the containers 25 also to take the form of electrically operated temperature-controlling grids.

The temperature-controlling means 25,26 is situated within an enclosure 27 in the form of a vat releasably connected through a suitable locking mechanism in a fluidtight manner to the bed 14. The bottom wall of the enclosure 27 extends parallel to the upper surface of the bed 14 and serves to carry the fans 26. These fans are fixed to the bottom wall of the enclosure 27 in such a way that the fan blades are situated within the enclosure just above-the bottom wall thereof while the driving motors for the blades are situated at the exterior of the enclosure 27 just beneath the bottom wallthereof. In this way the heat which is developed by the driving motors themselves will not falsify the temperature that is controlled by the temperature-regulating elements 25.

As a result of the enlarged exterior surface and enlarged mass, provided for the bed 14, the airstream can, by way of the cells 24, transfer the desired temperature to the bed [4 in a faultless manner so as to bring about a good and uniform distribution and storage of temperature within the bed 14. Any evaporation of the moisturizing water is practically prevented.

The embodiment of the invention, illustrated in FIGS. 2 and 3, provides temperature regulation by way of a liquid. In this case, too, the bed 14 is provided with the downwardly extended ribs 23 which again form cells 24. Pipes 28 extend into the cells 24 and terminate at their upper ends in spray nozzles 29. Each cell will have in its interior at least one spray nozzle 29 situated, for instance, in the manner illustrated in FIGS. 2 and 3.

The piping 28 forms part of and communicates with a piping network which is supplied with the temperature-regulating liquid through one or more supply pipes 35, the liquid being preferably water or thinned oil. The liquid is derived from a temperature-controlling unit which communicates with the piping network to supply the liquid thereto at a predetermined temperature. The piping 28 together with the spray nozzles 29 as well as the entire network of piping are situated within an enclosure 27a in the form of a vat which, through suitable releasable lock elements, is removably connected in a watertight manner to the bed l4.

The floor of the vat 270 has a substantially funnel-shaped configuration and has at its lowest point a discharge or return pipe 32 which returns the liquid to the temperature-controlling unit from which the liquid is derived to be sent through the referred to piping network and piping 28 to the nozzles 29. The liquid which is maintained at a predetermined temperature is sprayed against the upper end surfaces of the cells 24, these surfaces being situated directly beneath the upwardly directed surface of the bed 14, supporting the printing plate, so that a uniform temperature control of the entire bed and in particular of the upwardly directed printing plate-engaging surface thereof is achieved. The liquid which runs off from the ribs 23 serves to control the temperature of the latter as well so that because of the large mass of the bed 14 a steady, precisely determined temperature control of the bed and especially of the upwardly directed surface thereof is achieved in an entirely satisfactory manner.

lclaim:

1. In a flat offset press, a printing plate bed having an upper surface for carrying a printing plate and having at its side which is directed away from said upper surface a plurality of intersecting strengthening ribs defining box-shaped cells respectively having open bottom ends and terminating in upper closed ends defined by surface portions of said bed directed away from upper surface thereof, temperature-regulating means situated in the region of said cells for maintaining said bed at a given temperature, and an enclosure extending beneath said cells and enclosing said temperature-regulating means.

2. The combination of claim 1 and wherein said temperature-regulating means includes containers through which a fluid temperature-regulating medium flows and fans directing an airstream past said containers to said cells.

3. The combination of claim 2 and wherein said fans and containers are uniformly spaced from said cells.

4. The combination of claim 3 and wherein said enclosure has a wall situated beneath and extending substantially parallel to said upper surface of said bed, said, fans including fan blades situated within said enclosure adjacent said wall thereof and motors operatively connected :with said blades for rotating the latter and situated at the exteripr of said enclosure on the side of said wall thereof opposite from said blades.

5. The combination of claim I wherein said temperatureregulating means includes spray nozzles respectively situated within said cells, and piping communicating with said nozzles for supplying a temperature-regulating fluid stream thereto.

6. The combination of claim 5 and wherein said enclosure is of a substantially funnel-shaped configuration and is provided with a discharge conduit for returning fluid to a location from where it will again be delivered through said piping to said nozzles.

7. The combination ofclaim l and wherein said enclosure is removably connected to said bed.

8. The combination of claim 7 and wherein said enclosure is fixed in a fluidtight manner to said bed. 

